My only thought is no...I'm not aware of any after market lower seat...
I have removed mine,trimmed foam and replaced it with better foam... so if one really wanted to,they could trim and stuff a seat to there liking....
I suspect that if the entire couture were reduced 3 inches and a inch of gel or memory foam were placed back,you could reduce the height a couple of inches....
Customize it....
Lower the suspension a inch...different rear shocks and fork springs...Just don't go extreme and drop it to it's ankles.